1. Field of the invention
This invention relates to the insertion of a catheter into a vein or other vessel of the human or animal body via a peel sheath, such as in the insertion of Hickman/Broviac Long Term Venous catheters, and is particularly concerned with a device for facilitating the catheter insertion and the removal of the peel sheath.
2. Summary of the prior art
In general, the insertion of such catheters is carried out as follows. Firstly, a hollow needle is inserted into the selected vessel, and a flexible guide wire having a non-injuring leading end (known as a Seldinger wire) is pushed into the vessel through the needle. The needle is then removed from the vessel and the guide wire, and a tubular vessel dilator having a tapering leading end is inserted into the vessel to the required position over the guide wire, followed by a thin plastics tube, known as a peel sheath which is a close sliding fit on the vessel dilator. The guide wire and the vessel dilator are then withdrawn from the vessel and the peel sheath so that the catheter can be introduced into the vessel through the peel sheath. Finally, when the catheter has been inserted as required, the peel sheath is removed.
However, since it will often not be possible to withdraw the peel sheath along the whole length of the catheter because the entry point of the catheter into the body may be elsewhere, particularly in the case of a long term deep vein insertion, the peel sheath is designed to be removed by splitting its proximal end and pulling the split portions apart so that the sheath tears or peels in two along its entire length as it is withdrawn from the vessel. The problem with this arrangement is that if two hands are used to pull the sheath apart, as is often necessary, there is a tendency for the catheter to be drawn out of the vessel with the sheath unless someone else holds the catheter in place. Furthermore, in the case of a venous insertion there is often considerable haemorrhage through the sheath, even though the catheter is a close fir within the peek sheath, because of the distortion of the sheath induced by the peeling process and the pressure of the blood in the vein.